Think the problem is now finally located

fda-container-service/rest-service/src/test/java/at/tuwien/service/ContainerServiceIntegrationTest.java

@@ -79,7 +79,7 @@ public class ContainerServiceIntegrationTest extends BaseUnitTest {
 
         /* mock data */
         userRepository.save(USER_1);
-        final ContainerImage tmp = ContainerImage.builder()
+        imageRepository.save(ContainerImage.builder()
                 .id(IMAGE_1_ID)
                 .repository(IMAGE_1_REPOSITORY)
                 .tag(IMAGE_1_TAG)
@@ -91,8 +91,7 @@ public class ContainerServiceIntegrationTest extends BaseUnitTest {
                 .size(IMAGE_1_SIZE)
                 .environment(IMAGE_1_ENV)
                 .defaultPort(IMAGE_1_PORT)
-                .build();
-        imageRepository.save(tmp);
+                .build());
     }
 
     @AfterEach

fda-metadata-db/entities/src/main/java/at/tuwien/entities/container/Container.java

@@ -64,6 +64,7 @@ public class Container {
     })
     private List<Database> databases;
 
+    @org.springframework.data.annotation.Transient
     @ManyToOne(fetch = FetchType.LAZY, cascade = CascadeType.MERGE)
     private ContainerImage image;